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Adaptation in the seaweed fly Coelopa frigida

Rosenquist, Hanna (2017) BIOP34 20141
Degree Projects in Biology
Abstract
Patterns of local adaptation are expected to emerge when selection is spatially heterogeneous and sufficiently strong relative to the action of other evolutionary forces. The observation of local adaptation thus provides important insight into evolutionary processes and the adaptive divergence between populations. The seaweed fly Coelopa frigida exhibits an inversion polymorphism in all populations sampled, including those along the southern Swedish coasts, where a cline of inversion frequencies has been previously described. I used a reciprocal transplant experiment to test for local adaptation in four populations situated along this previously cline. My results show evidence for adaptation in two of the four populations, indicating that... (More)
Patterns of local adaptation are expected to emerge when selection is spatially heterogeneous and sufficiently strong relative to the action of other evolutionary forces. The observation of local adaptation thus provides important insight into evolutionary processes and the adaptive divergence between populations. The seaweed fly Coelopa frigida exhibits an inversion polymorphism in all populations sampled, including those along the southern Swedish coasts, where a cline of inversion frequencies has been previously described. I used a reciprocal transplant experiment to test for local adaptation in four populations situated along this previously cline. My results show evidence for adaptation in two of the four populations, indicating that local selection is strong. In addition, when flies from the same parents were grown on different wrackbed substrates, pronounced differences in development time, survival, morphology and in some instances also karyotype frequencies were recorded, indicating strong gene x environment interactions. It was also noted that the mean development time differed between the sexes when all data was pooled, with males taking on average one day longer to develop. This may be linked to the α inversion that increases body size in males. It is noteworthy that we not only found consistent strong karyotype morphology interactions across the treatments (ββ<αβ<αα), but we also found a similar effect in females. A karyotype effect on body size in females has not been shown before. Together, my experiment revealed complex interactions between fly origin, wrackbed substrate, sex and morphology. These results demonstrate that the environmental conditions that the flies experience during larval development have clear and strong effects. It is likely that the ability of the flies to respond to their habitat in varied ways allow them to inhabit a wide ranging over significant environmental gradients. Future work would benefit from investigating the genomic underpinnings of the causative genes inside and outside the inversion to gain more insights into mechanisms that allow them to survive in often remarkably different environments. (Less)
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author
Rosenquist, Hanna
supervisor
organization
course
BIOP34 20141
year
type
H2 - Master's Degree (Two Years)
subject
language
English
id
8906079
date added to LUP
2017-04-24 11:09:41
date last changed
2017-04-24 11:09:41
@misc{8906079,
  abstract     = {Patterns of local adaptation are expected to emerge when selection is spatially heterogeneous and sufficiently strong relative to the action of other evolutionary forces. The observation of local adaptation thus provides important insight into evolutionary processes and the adaptive divergence between populations. The seaweed fly Coelopa frigida exhibits an inversion polymorphism in all populations sampled, including those along the southern Swedish coasts, where a cline of inversion frequencies has been previously described. I used a reciprocal transplant experiment to test for local adaptation in four populations situated along this previously cline. My results show evidence for adaptation in two of the four populations, indicating that local selection is strong. In addition, when flies from the same parents were grown on different wrackbed substrates, pronounced differences in development time, survival, morphology and in some instances also karyotype frequencies were recorded, indicating strong gene x environment interactions. It was also noted that the mean development time differed between the sexes when all data was pooled, with males taking on average one day longer to develop. This may be linked to the α inversion that increases body size in males. It is noteworthy that we not only found consistent strong karyotype morphology interactions across the treatments (ββ<αβ<αα), but we also found a similar effect in females. A karyotype effect on body size in females has not been shown before. Together, my experiment revealed complex interactions between fly origin, wrackbed substrate, sex and morphology. These results demonstrate that the environmental conditions that the flies experience during larval development have clear and strong effects. It is likely that the ability of the flies to respond to their habitat in varied ways allow them to inhabit a wide ranging over significant environmental gradients. Future work would benefit from investigating the genomic underpinnings of the causative genes inside and outside the inversion to gain more insights into mechanisms that allow them to survive in often remarkably different environments.},
  author       = {Rosenquist, Hanna},
  language     = {eng},
  note         = {Student Paper},
  title        = {Adaptation in the seaweed fly Coelopa frigida},
  year         = {2017},
}